Pros:
+ Campaign is amazing - historical documentary style story telling feels like it was pulled straight out of those old History Channel shows.
+ Civs numbers may seem small compared to other AoE titles, but Relic has done a great job differentiating each civilization with their own unique economic bonuses, technologies, and units.
+ Unique playstyles per civ makes them play differently
+ On-boarding for new players is very thorough. Tutorial is easy to follow and Challenge modes allow players to test how optimized their playstyle is to a limited extent.
+ Standard game modes are there (Campaign, Skirmish, Coop Vs AI, 1v1, Team VS, FFA, etc.)
+ Mastery System for each civ introduces each of their unique playstyle/techs with added challenge
+ Some small account personalization included (TC statue, player banner, etc.)
+ Decent map variety with typical AOE randomization adds additional replayability.

Neutral:
= Aesthetics of projectiles/weapons aren't the best (e.g. too large, fly in weird angles, etc), but after a while you start to appreciate the clarity they provide
= Art style is more colorful. Very painterly/tapestry-like, which may not appeal to everyone's taste.
= Pure RTS game through and through. While it brings mechanics from other RTS titles, AOE4 does not really innovate on much of the mechanics seen from games before it.

Cons:
- Some imbalance with civs, which is expected with a new RTS ( as of this writing French and Mongols are on the stronger side).
- Plenty of bugs and issues:
- Civ bugs make them underpowered (HRE Prelate, Nest of Bees, etc.)
- Or overpowered (Mongol speed bug)
- Replay and post game charts has some bugs that displays incorrect information

Overall, it's a very enjoyable game. Well worth it if you're into RTS games or looking to get into the genre. With enough support from Relic and Microsoft, this is a game I'll keep coming back to.